Most interval sessions are pretty straightforward in their construction: X number of [fill in the blank] intervals @ Y pace with Z recovery between repetitions. There’s nothing wrong with these types of workouts. They’re easy to understand and effective at producing a desired adaptation. Hammer intervals, made popular by coach Scott Simmons of the American Distance Project, throw a slight twist into the mix: every third or fourth repetition (whatever cadence you choose, really), you “hammer” it (i.e. run it quite a bit harder) before returning to the prescribed pace. The catch? You don’t get any more recovery time after the hammers than you do the other intervals in the session. Here are the details:
What: A set of intervals in which you “hammer” every third or fourth repetition and run the rest of them at the same pace. The recovery time after each interval, even the “hammers,” remains consistent throughout the workout. A few examples of Hammer Intervals are: 1. 12 x 400m @ 3K pace w/75 seconds recovery between reps. “Hammer” #s 4, 8, and 12 @ 1-mile pace. 2. 8 x 800m @ 5K pace w/2 minutes recovery between reps. “Hammer” #s 4 and 8 @ 3K pace. 3. 6 x 1 mile @ 10K pace w/2:30 recovery between reps. “Hammer” #s 3 and 6 @ 5K pace.
Warmup/Cooldown: Warm up before the workout with 15-30 minutes of easy running followed by a set of drills and 4-6 x 20-second strides (i.e., accelerate for 5 seconds, spend the next 10 seconds at near-top speed, and then gradually decelerate to a jog over the final 5 seconds. Catch your breath for 40-60 seconds and then repeat 3-5 more times). Cool down after the workout with 5-15 minutes of easy running.
Why: The “hammer” interval increases your level of fatigue and compromises your recovery during the workout, teaching you how to run hard when tired, thus simulating what happens in a race situation.
When: Only after you’ve got a few weeks of consistent workouts under your belt! This is an advanced workout that should only be attempted when you’re decently fit because it takes a little longer to recover from than a typical interval session. I would not recommend Hammer Intervals within a week of a key race.
Where: Track, road, trail, or treadmill, you can do this workout wherever you usually do interval sessions.